The White House says President Barack Obama has canceled a planned meeting with Philippine President Rodrigo Duterte, after the blustery Philippine leader, in comments to reporters, used a vulgarity in referring to the U.S. commander-in-chief.

Obama said earlier that he planned to use an expected meeting with Duterte at a summit in Laos to raise the issue of more than 2,000 extra-judicial killings of suspected Philippine drug dealers and users since Duterte took office in June.

For his part, Duterte has defended his support for the killings, saying he is following the will of those who elected him. Then, before departing Manila on Monday for the Lao capital, Vientiane, he warned Obama: "You must be respectful. Do not just throw questions." Using the Tagalog phrase for "son of a bitch," he then said: "Putang ina, I will swear at you in the forum."

Obama initially shrugged off Duterte's comments, noting that "clearly [Duterte] is a colorful guy." But he also said the planned meeting hinged on whether Duterte was prepared for "constructive, productive conversations."

Hours later, National Security Council spokesman Ned Price said the Tuesday meeting with Duterte had been canceled and that Obama would instead meet with South Korean President Park Geun-hye.

Duterte, who campaigned for the Philippine presidency on promises to end illegal drug activity in his homeland, has alarmed an array of human rights organizations with his deadly crackdown. He also has vowed to defend police and the Philippine military carrying out his orders, even at the cost of his own possible imprisonment.